Slip stitch sewing machine



Nov. 16, 1937. H. ROSENMAN ET AL 2,099,574

SLIP STITCH SEWING MACHINE Filed April 19, 1935 7 Sheets-Sheet l g mvg sr Y 7mm Nqv. 16, 1937. H. ROSENMAN ET AL SLIP STITCH SEWING MACHINEFiled April 19, 1955 7 Sheets-Sheet 3 INVEN Rs W TTbRNEY Gar mevrt' v H.ROSENMAN ET AL- SLIP STITCH SEWING MACHINE 7 SheetsSheet 4 Filed April19, 1955' 2. INVENT 5 M ATTORNEY Nov.. 16, 1937. H. ROSENMAN ET AL SLIPSTITCH'SEWING MACHINE Filed April 19, 1955 7 Sheets-Sheet 5 V INVENTO lfiTTORNEY' 6 5 05 1 7 0 0 m w oi M; i- WW w LE T A J i Nov. 16, 1937. IH.ROSENMANQET AL 4 SLIP STITCH SEWING MACHINE Filed April 19, 1935' 7Shee ts-Sheet 6 iNvENT M BY 4 W ATTORNEY 7 Sheets-Sheet 7 Filed April19, 1955 4 INVE OR M z 7ATTbRNEY Patented Nov. 16, 1937 PATENT OFFICEsur s'rrrcn sswmc. MACHINE Herman Rosenman and Leo Roseman,

Newark, N. J.

Application April 19, 1935, Serial No. 17,160

30 Claims.

This invention relates to a sewing machine especially for skipping orslipping of stitches in a line of stitches according to a methoddescribed and claimed in the application of Herman -Rosenman filedFebruary 19, 1935, Serial No.

While our machine. is useful for many purposes, it is particularlydesirable for stitching together two or more plies or thicknesses ofmaterial with continuous lines of stitches where-- in at predeterminedintervals stitches are skipped or slipped to form gaps between twoadjacent plies to receive fastener elements such as hooks or eyes forexample to form fastener tape or to receive clasps of clasp steels orthe like at the edges of corsets.

Our invention contemplates a machine wherein a needle forms a loop inthe thread which is picked up by a loop taker and interlocked withanother thread, for example, from a bobbin mechanism, for completing astitch during normal operation of the machine, although the invention issusceptible to use with other types of sewing machines, includingmultiple needle ma- 3 chines.

It has been proposed to skip stitches in a line of stitches formed by asewing machine, either by interrupting the reciprocation of the needlebar so that the needle is prevented from penem crating the work, or bythrowing the needle bar out of cooperation with the loop taker of thebobbin mechanism, or by throwing the loop taker out of cooperatingrelation with the needle, so that the loop taker cannot pick up the loopwhich is formed by theneedle during normal operation in making a stitch.All of these machines involve complex mechanisms and opera- -tions andrequire modification of the usual stitch forming mechanism foraccomplishing the skipping of stitches, and furthermore in these Inother cases, stitches are skipped underma chines no provision is made totake up or compensate for the surplus thread which results from theskipped stitches, so that the thread tangles.

erly located, and the operation is tedious and slow.

Prime objects of our invention are to provide a sewing machine-embodyingnovel and improved features of construction whereby one or more 5stitches can be slipped or skipped automatically by manipulation orcontrol of the thread independently of the normal stitch formingmechanism of the sewing machine instead of modifying or manipulating theloop taker oi the bobbin mechanism or the needle bar; and to providesuch a machine whereby the skipped or slipped stitches shall be locatedaccurately and automatically by the machine and the operation of forminga line of stitches including skipped or slipped stitches shall be rapidand require a minimum of manual effort and attention. Our invention isparticularly directed to means for pulling of the thread so as toprevent the formation of a loop in the thread and thereby preventcooperation of the loop taker with the needle thread to prevent theformation of a stitch or stitches.

In normal, operation, the loop of course requires a predeterminedquantity of thread, and the loop is formed normally during withdrawal ofthe needle from the work but before the needle is disengaged from thework. In accordance with our invention novel and improved means isprovided to exert tension on the needlethread during withdrawal of theneedle from the work and at the same time withdraw from the work intimed relation to the movement of the needle a predetermined or measuredquantity of thread which is necessarily present to permit formation of aloop to cooperate with the loop taker, so as to' ensure that enoughthread shall be Withdrawn to prevent formation of the loop and at thesame time the thread shall not be broken by excess tension.

Further objects are to provide in a machine of the character describednovel, improved and simple means for controlling or withdrawing thethread automatically in a. regular cycle in timed relation to themovement of the needle and independently of or without afi'ecting thenormal operation of the stitch forming mechanism or the work feedmechanism of the machine; and thus to provide sucha machine which shallbe capable of forming a line of stitches in the usual way, incombination with novel and improved mechanism for-gripping the thread ata certain time above the eye of the needle while the needle is inapproximately its uppermost position and preferably while the thread istaut between the point of gripping and the point of interlockin of thethread in vthe work on the last previously formed stitch, thenmanipulating the thread in timed relation to the movement of the needleto prevent formation of a stitch, and thereafter releasing the grip onthe thread whereby it shall be possible to form a line of stitchinghaving skipped stitches spaced along the line accurately at desiredintervals.

Further objects are to provide such a machine which shall include noveland improved means for timing the spacing of the skipped or slippedstitches so that said skipped stitches may be located at predeterminedintervals; and thus to provide means preferably actuated approximatelysynchronously with the "drive shaft and needle bar of the machine forpulling or manipulating the thread, in combination'with means operablein timed relation with but at slower speed than said drive shaft andneedle bar to control the gripping of the thread by the pulling ormanipulating means.

Another object is to provide a machine of the character described whichshall include novel and improved means for moving or controlling thesurplus thread that is present due to skipping of a stitch, so that saidsurplus thread shall be prevented from becoming entangled with theneedle and thereby obviate breaking of the thread during formation ofsubsequent stitches.

In many cases, it is desirable that a skipped stitch be located acertain distance from the edge of a piece of work at the beginning ofthe stitching 'operatlon, and therefore another object o! my inventionis to provide novel and improved indicator means for pre-setting themachine so that the first skipped stitch in a piece of work shall belocated at the desired distance from the edge of the work at thebeginning of the stitching operation, or to indicate the number ofstitches that have been made after a slip stitch.

It is often necessary that the slipped stitches be exactly spaced in thework, especially in making a fastener strip where the gaps resultingfrom the slipped stitches are intended to receive fastener elements tocooperate with complemental fastener elements on another fastener strip;and therefore our invention contemplates mechanism for slipping orskipping stitches including a reciprocating feed dog, in combinationwith auxiliary positive work advancing means ahead of the feed dog, forexample continuously rotating feed rollers to grip the work betweenthem, for

preventing underfeeding or overfeeding of the work by the feed dog.

In applying strips to the edge of a garment and skipping or slippingstitches to leave gaps for fastener elements, as hereinabove described,it is desirable in many instances that the slip stitches be located incertain relations to the garment, for example that the last slippedstitch be spaced a certain distance from the end of the garment, and theoperator can see that with continued feeding of the work with normal orusual feed of the work, the last slipped stitch will not be properlylocated. Therefore, another object is to provide such auxiliary workadvancing means in combination with the usual feed dog work feedmechanism whereby the feed of the strips and garment may be modified atthe will of the operator for various purposes, for example, to cause thelast slipped stitch to be located at least approximately at the desiredpoint.

A further object is to provide novel and improved means in a machine ofthe character described for throwing the thread gripping or controllingmechanism out of or into. operation at will, so that it shall bepossible to form a continuous line of stitches without skipping stitcheswhenever desired.

Other objects are to provide means which can be applied to many knowntypes of sewing machines for controlling or manipulating the threadwithout modification of the usual stitch forming mechanisms or work feedmechanisms, and to obtain other advantages and results as will bebrought out by the following description.

Referring to the accompanying drawings, in which corresponding and likeparts are designated by the same reference characters,

Figure 1 is a topplan view of a sewing machine embodying my invention.

Figure 2 is a front elevation thereof.

Figure 3 is an end elevation of the machine showing the thread grippingmechanism in the position which it takes at the beginning and the end ofthe thread control movement.

Figure 4 is a similar view showing the thread gripping mechanism in theposition which it takes just prior to the pulling of the thread to skipa stitch.

Figure 5 is a detached top plan view of the thread gripper.

Figure 6 is a fragmentary top plan view of the cam mechanism forcontrolling the gripping of the thread showing the cam in the positionassumed just prior to the thread gripping operation.

I Figure '7 is a schematic perspective view of the thread grippingmechanism with the parts in the positions assumed just prior to grippingof the thread.

Figure 8 is a view similar to Figure 6 showing the position of the camduring gripping of the thread.

Figure 9 is a view similar to Figure '7 showing the position of theparts just prior to the beginning of the thread pulling operation.

Figure 10 is a view similar to Figure 8 showing the position of the camat the end of the thread pulling operation.

Figure 11 is a similar view showing the position of the cam just afterrelease of the thread by the gripper.

Figure 12 is an enlarged transverse vertical sectional view through aportion of the needle and work illustrating the position of the needleat the beginning of the formation of a stitch as shown in Figure 3.

Figure 13 is a similar view showing the needle in the limit of itspenetration of the work and just prior to the beginning of the formationof the thread loop.

.Figure 14 is a similar view showing the risin of the needle and thenormal formation of the loop in the needle thread.

Figure 15 is a like view showing the rising of the needle and thepulling of the thread to prevent the formation of a loop.

' Figure 16 is a similar view showing the three 8. completely pulledfrom the work.

Figures 17, 18, l9-and 20 are fragmentary schematic side views'of theparts for throwing the tlgjread gripping mechanism into and out of operaon.

Figure 21 is a top plan view of a machine showing a modification of theinvention.

Figure 22 is a front elevation thereof.

Figures 23 and 24 are end elevations corresponding to Figures 3 and 4.

Figure 25 is a detached perspective view of one of the parts of thethread gripper.

Figure 26 is a schematic perspective view of the thread grippingmechanism shown in Figures 21 to 24 inclusive illustrating the parts inthe positions assumed just prior to gripping of the thread.

Figure 27 is a similar view showing the parts in the positions assumedjust prior to pulling the thread.

Figure 28 is a fragmentary schematic perspective view showing theoperation of the means for throwing the thread gripping mechanism intoand out of operation.

Figure 29 is a top plan view of the indicator for presetting the machineto locate the first skipped stitch a predetermined distance from theedge of the work at the beginning of the stitching operation, or forindicating the number of normal stitches that have been formed after aslip stitch.

Figure 30 is an enlarged longitudinal vertical sectional view throughwork having a line of stitches therein and illustrating the skippedstitch.

'Figure 31 is a fragmentary perspective view of two superposed plies ofmaterial stitched together with a line of stitches in accordance withthe invention.

Figure 32 is a rear perspective view showing the plies of materialfolded backwardly upon each other.

Figure 33 is a front perspective view corresponding to Figure 32.

Figure 34 is an enlarged transverse vertical sectional view through theplies shown in Figures 32 and 33 with a fastener strip insertedtherebetween and a fastener projecting through the gap formed by theskipped stitch.

Figure 35 is a top plan view of a modified form of thread gripperespecially designed for use with two needle machines.

Figure 36 is a perspective view of two superposed strips of fabric for afastener tape having two lines of stitches formed with a two needlemachine and having corresponding slipped stitches to form a gap for afastener element, and

Figure 3'7 is a similar view showing a line of stitches formed withan'oscillatory or so-called zig-zag machine and having a slipped stitch.

For the purpose of illustrating the princ ples of our invention we haveshown it schematically in connection with a known type of sewing machinewhich includes the usual frame 6 having the usual stitch formingmechanism including a needle bar A reciprocable therein by knownmechanism (not shown). The needle bar carries the usual needle 3, andthe machine also includes a take-up lever l which is utilized forsupplying and taking up the thread in cooperation with the loop taker.The needle has the usual eye 6 and the longitudinal groove i at one sidein which the thread is seated as the needle penetrates and is removedfrom the work which is designated W.

Cooperating with'the needle bar is thebobbin mechanism 5 of known typewhich includes a loop taker hook 8 to pick up the loop formed in theneedle thread during-the normal operation of the machine in theformation of a stitch.

The machine also includes suitable known work feed mechanism whichincludes the reciprocating feed dog R for advancing the work beneath theneedle in steps each equal'to the length of one stitch, and a presserfoot P of known structure. is included to hold the work against the feeddog. For the sake of simplicity these parts are only schematically andfragmentarily illustrated.

As usual, the thread T is threaded from a supply spool or the likethrough the tension device 5, the eye of the take-up lever 4 and the eyeof the needle 6, and during normal operation of the machine'the needlereciprocates and on its descent penetrates the work to carry the threadthrough the work as shown in Figure 13 of the drawings. As the needlerises, normally the thread at one side of the needle frlctionallyengages the work while the thread at the other side of the needle is inthe groove I, so .that as the needle rises a loop L in the thread isformed below the work, as shown in Figure 14, andthis loop is picked upby the loop taker 8, carried around and interlocked with the bobbinthread to form a stitch S indicated in Figure 30. After the needleleaves the work, the work feed mechanism R moves the work forwardly adistance equal to the length of one stitch, preparatory to the next workpenetrating movement of the needle for the next stitch. When the needleis in its uppermost position, the thread between the take up lever andthe point in the work where the threads are interlocked to form .thelast previously formed stitch,

is substantially taut, and there is suflicient thread present to form aloop for the next stitch.

As above indicated, when it is desired to slip a stitch, we propose tomanipulate or control the thread T so as to prevent the formation of theloop L; and when it is desired to slip a stitch Now specificallydescribing the thread gripping and pulling mechanism, said mechanismincludes a gripper G which comprises two gripping jaws i0 and ill one ofwhich is fixedly connected to a horizontal tubular shaft it? which ismounted on a bearing bracket it secured on the goose-neck of themachine. The other jaw ii is mounted on the end of a rod it which isslidable longitudinally of the tubular shaft 93 with one end projectingfrom the tubular shaft and in abutting relation to an adjustable screwi5 mounted in one end of a lever 96 which is pivotally mounted at i "iin the bracket 93 and connected to one end of a follower lever to whichcarries a roller is that follows a cam 20. The two jaws i0 and ii are injuxtaposed relation and receive the thread '1 between them, and the jawsare normally influenced together by tension spring 2! connected to a pin22 which is fixed in the jaw ii and slidable through the jaw ittransversely of the latter.

The pin 22 causes the jaws to swingtogether about the axis of the shaftit. As shown; the jaws are mounted for oscillation in a vertical planewhich is approximately the plane of the portion of the thread betweenthe take up lever t and the needle.

The jaws are oscillated and in timed relation with the drive shaft D ofthe machine and the needle bar by a cam 23 which is mounted on the driveshaft (see Figure 7). The cam 23 cooperates with the follower roller 32which is connected to a lever 3i pivotally connected at one end at 33 onthe machine and connected at its other end by a link 34 to a crank arm35 on the tubular shaft l2. The roller 32 is caused to follow the cam 23by a spring 36.

its lowermost work penetrating position shown in Figure 13. As theneedle rises the cam 23 actuates the gripper upwardly into the positionshown in Figures 3 and 7. The gripper jaws I0 and II as so controlled bymeans about to be described that during the withdrawal of the needlefrom the work the gripper pulls out an amount'of thread that is presentfor forming a loop so as to prevent formation of a loop as shown inFigure 15. During the movement of the needle to the point which locatesthe thread above the loop taker 8, the movement of the gripper is inadvance of the movement of the needle to ensure pulling out of thethread that is present for normal formation of the loop, and during theremainder of the upward movement of the needle the gripper preferablymoves at a speed to prevent the thread beneath the gripper becomingentangled with the point of the needle and this obviates breaking of thethread during formation of subsequent stitches.

The gripper jaws I0 and II are actuated toward and from each other togrip and release the thread by the cam 20 which actuates the followerlever I8, lever I6 and rod I4. This cam 20 is mounted on a verticalcountershaft 24 journaled in suitable bearings 25 connected to thegooseneck of the machine and is driven by worm and worm gear drive 26from the drive shaft D of the machine at a reduced speed. The speedratio between the shaft D and 24 may be as desired, for example so thatthe shaft 24 will make one revolution for a given number of stitches.One stitch is made during each revolution of the shaft D as usual, andas shown the speed ratio is twelve to one; in other words the cam 20will make one revolution while the drive shaft D is making twelverevolutions which during normal operation of the machine will result inthe formation of twelve continuous stitches for each revolution of thecam 20. In the present instance it is desired that one stitch shall beslipped in each series of twelve stitches, in other words, that elevencontinuous stitches shall be formed and then one stitch shall beslipped. For this purpose the cam 20 has a concentric dwell 21 withwhich the follower roller I9 contacts during the formation of elevenstitches, and a cam recess 28 which the follower roller engages duringthe interval required for formation of one stitch by the stitch formingmechanism.

The spring 2| normally holds the follower roller i4 in contact with thecam 20 and when the gripper is in its approximatey upper position thegripping jaws are separated so as to release the thread as shown inFigure 7, the follower roller and cam being in the relative positionsshown in Figure 6. As the follower roller 20 enters the cam recess 28.,the jaws are drawn together to grip the thread approximatelysimultaneously with the beginning of a downward movement of the gripperjaws, and the gripping relation to the thread is maintained throughoutthe work penetrating movement of the ,needle approximately synchronouslywith the movement of the thread. As the needle begins to rise, the cam23 and connected parts swing the gripper Jaws upwardly slightly inadvance of the normal movement of the thread so as to pull the threadout of the work to prevent the formation of a loop as shown in Figure15. The gripper need move in advance of the thread only during themovement of the needle to the point which locates the thread above theloop taker so as to ensure pulling out of the thread that is present fornormal formation of the loop, and during the remainder of upwardmovement of the lever the gripper preferably moves at a speed to take upthe thread beneath the gri per so as to prevent the thread from becomingentangled with the needle. Approximately as the gripper jaws reach theirupper position the follower roller is forced out of the cam recess asshown by Figures 10 and 11 so as to release the thread, and thereafterthe machine will continue to make stitches because while the gripperjaws may be continuously oscillated they cannot grip the thread andtherefore cannot pull out the thread to prevent formation of stitches.With this construction it will be observed that in operation of themachine, eleven continuous stitches will be formed followed by skippingof one stitch, after which eleven more stitches will be formed and soon.

Obviously by modifying the cams 20 and 29-I33 two or more stitches mightbe skipped in succession, and byvarying the timed relation between thestitch forming mechanism and the thread gripping mechanism, theintervals at which the skipped stitches will be formed may be .varled.

It is desirable to prevent oscillation of the gripper during the normalformation of stitches both to prevent unnecessary wear on the threadgripping mechanism and to avoid unnecessary noise. For this purpose, thecam 20 may have a. concentric cam surface 29 engaged by aroller 30mounted on the lever 3I to hold the follower roller 32 out of contactwith the cam 23 as shown in Figure '7 except during the operation ofskipping a stitch. To permit operation of the gripper for skipping thestitch, the cam surface may be interrupted by a recess I33 in properrelation to the cam recess 28 to permit the roller 30 to drop andthereby enable the follower roller 32 to follow the cam 23 as shown inFigure 9.

It will readily appear to those skilled in the art that the cam 23 andfollower roller 32 might P be eliminated, and the cam notch I33 modifiedto actuate the lever 3i and shaft I2 through roller 30 instead of usingthe notch I33 simply as a clearance for the roller 30 to permit theroller 32 to follow the cam 23.

It will be understood that during the pulling of the thread the workfeed R. will have moved the work forwardly in the normal way a distanceequal to the length of one stitch and the needle will have penetratedthe work so as to leave a hole 0 in the work as shown in Figure 30.Preferably the jaws will be released from the thread slightly beforethey reach their uppermost position of Figures 3 and '7 and will be heldreleased from the thread by the cam dwell 21 a sufficient time to permitthe take up lever 4 to adjust the thread for the next stitch.

It will be observed that the thread is maintained substantially tautbetween the needle and the gripper throughout the reciprocation of theneedle from the beginning of its descent as shown in Figures 3 and 7 toits lowermost work penetrating position shown in Figures 4 and 13, andthen through its upward movement back to its uppermost position; and dueto the constant grip on the thread during the movement of the gripperthere is; ensured the exact and measured amount of t d between the pointof gripping and the lnterloc oi the thread. in the .last previouslyformed stitch, by reason ofwhich formation of the loop may be positivelyprevented and breaking of the thread is obviated. Preferably the grip bythe jaws on the thread is frlctionally yielding so that the thread maybe pulled through the operation of the -stitch forming and 'work feedmechanism of the machine.

Where it is desired to throw the thread grip- .ping and pull mechanismout of operation, for

example to form a continuous line 01 stitches without skipping stitches,we may utilize a control device including a lever pivotally mountedintermediate its ends at 4! on the machine and which may be manuallyoperated. Oneend of the lever has a pin and slot connection 42 with aeontrolslide 43 mounted in the top of the machine to cooperate with anextension 44 on the lever 3|. The slide 43 moves transversely of theextension 44 and has a lug 45 at its extremity and an inclined or,wedging surface 46 adjacent said lug. When the gripper has been movedto its upper position as shown in Figures 3 and 7 the slide may bepushed beneath the extension 44 as shown in Figure 18, and uponcontinuation of this movement of the slide the wedge or inclined portion46 will engage the extension to'swing the gripper furtherupwardly toclear the follower roller 22 from the cam 23 as shown in Figures 19 and28 and thereby completely disconnect the gripper from the drivingmechanism. Therefore, it will be observed that with the parts in thepositions shown in Figures 19 and 20, the gripper cannot operate, and inorder to permit operation of the gripper the slide '43 must bedisengaged from the extension 44 as shown inFigure 18. Due to the lug 45operation of the gripper cannot be started until it reaches its upperposition because as shown-in Figure any attempt to disengage the slide43 from'the extension 44 while the gripper is below its uppermostposition is prevented by engagement of the lug 45 with the extension.

It will alsobe observed that when the gripper is in its intermediate orlower positions as shown in Figures 4 and 9 the slide cannot be slidunder the extension 44 as shown in Figures 9 and 17 and therefore theoperation of the gripper cannot be stopped until it has reached itsuppermost position as shown in Figures 7 and 18.

From the foregoing, it will appearthat the thread gripping and pullingmechanism may be thrown into and out of operation at will by operationof the lever 40, and when out of operation it will always be located atits uppermost position as shown in Figures 3 and '7. While the threadgripping'mechanism is out of operationthe stitch forming and work feedmechanism will make a continuous line of stitches, while when thecontrol slide 43 is disengaged from the extension 44, a stitch will beskipped at predetermined intervals, in the present instance every out ofoperative relation to the cam 20 when oscillation'of the thread gripper"is stopped by the control slide 43 and for this purpose, the V lever 40may have a lug 450 to engage the 101- lower lever It so as to swing thelatter to slidethe gripper jaw l I away from the jaw l0 simultaneouslywith the movement oifthev control slide 43 beneath the extension 44.Obviously, the lever 40 will be so mounted asto overcome the resist anceof the spring 2|. As shown, thelever 4|! and slide 43 are mounted on aplate secured to the top of the goose-neck of the machine, and

the follower lever l8 projects through a slot"- in said plate.

While the form of the gripper jaws I0 and, II may be considerablyvaried,a satisfactory structure is shown in the drawings, particularly Fig-'ures 4 and 5 wherein one of the gripper jaws has a spring wire loop 62through which the thread is passed and which holds the thread inapproximately proper relation to the gripping surface of the jaws, andthe other jaw has a guide plate 53 formed with a slot 54 to receive thethread and hold it in exactly the proper relation to the grippingsurfaces.' The movable jaw may move relatively to the guide plate 53.

In some cases it may be desirable toform a groove I96 in one of thegripping jaws of a' depth less than the diameter of the thread to ensurethat the thread shall always be gripped between the same portions of thegripping surner as shown in Figures 1 and '7,'namely' by the spring 2|.In operation, when the gripper is in approximately its uppermostposition, the

gripping jaws are brought into engagement with the wedge GI and areseparated by the wedge so as to release the thread as shown in Figure26, the upward movement of the gripper under the influence of the cam 23forcing the jaws illand II over the wedge so that the jaws are spread'apart; and when the cam 23 permits the gripper to move downwardly underthe influence of the spring 36, the jaws are slipped oil. the wedge andmoved together by the spring 2i to grip the thread as shown in Figure27.

For controllingthe oscillation of the jaws so as to skip a stitch'atproper intervals, we utilize a cam 63 having a surface similar to thecam surface 29 and mounted on the countershaft 24 and formed with.- acam .notch 64 to cooperate with a roller 65 corresponding to the roller30 of Figure '7. One revolution of the cam 63 corresponds to twelvestitches and while the roller 65 5" is in engagement with the fiat camdwell 66, the gripper jaws are, held in their uppermost position,separated by the wedge 6i. When the cam has been rotated to the pointwhere the roller 65 may drop into the notch 34', thegripper jawsareswungdownwardly under the influence of;

the spring 36 'under control of the cam 23, and

are then raised. by the cam 23 to move the roller out of the notch so asto be again engaged by the. dwell 66. The speed and character of Figures1 to 11 inclusive, the cam 88 and wedge 8| in effect taking the place ofthe cam 20, the follower roller l8 and the levers l8 and l8.

To illustrate the character of the skipped or slipped stitch formed bythe machine, we have shown in Figure 30 complete stitches S and aslipped or skipped stitch K. It will be noted that between the twostitches S the needle thread T and bobbin thread T-T haye not beeninterlocked as they are at -U when the stitches areformed.-

Furthermore to illustrate one possible use of the machine we have shownin Figures 81 to 34 inclusive work of one type that can be performedwith the machine. In Figure 31 are shown two plies of material 10 and 1|stitched together adjacent their edges by a line of stitches 12including a skipped' stitch 18. In Figure 32 the two plies are shown asfolded backwardly upon each other after stitching, and Figure 33illustrates the two folded plies with a gap 14 therebetween left by theskipped stitch 18. In Figure 34 the two plies of material are shown ashaving between them a fastener strip 18 which has a fastener such as awire eye 18 projecting through the gap 14. The structure shownconstitutes one type of garment fastener and may be embodied directly inthe edge of a garment or may be composed of strips of material which maybe secured to the edges of a garment.

In making such fastener tape, it is highly desirable that the gaps 14 beaccurately spaced, and our machine makes this possible automatically.The usual feed dog work feed mechanism is not sufficiently reliable toproduce the necessary accuracy and to ensure that the work shall be feduniformly and accurately, we utilize an auxiliary feed mechanism tocooperate with the usual feed dog illustrated in Figure 3. Thisauxiliary feed mechanism includes two serrated feed rollers8|l and 8|between which the material to be operated upon is gripped, one rollerbeing mounted in the frame of the machine on shaft 88 and the othermounted on a shaft 84 in a frame 840 pivoted at 84| so that roller 8|may be influenced toward roller 88 by a spring 842. The rollers aregeared together to rotate at the same peripheral speeds by intermeshingpinions 82, one on each of the roller shafts 83 and 84, and-one of theshafts, in the present instance the shaft 83, is driven by a helicalgear connection 85 with a jack shaft 88 which has a helical gearconnection 81 with the counter-shaft 24. The rollers 80 and 8| morefirmly grip the work than do the presser foot and feed dog, and feed thework accurately in timed relation to the stitch forming mechanism. Thefeed dog is normally adjusted to feed a length of work slightly greaterthan the length supplied by the feed rollers for each stitch to ensurethat the full amount of work shall be brought to the needle, and thepressure of the feed dog on the work'is such that it may slip beneaththe work after it has fed the exact amount controlled by the feedrollers. With this construction, the work is positively gripped betweenthe feed rollers 88 and 8| and the rollers are constantly rotated at auniform speed in timed relation to the drive shaft D and the needle, sothat the work may be fed with extreme accuracy and the skip stitches18may be accurately spaced in the work and overfeed of the work isprevented. Underfeed also is prevented by the adjustment of the dog R tofeed more than desired, and the preventing of excess feed by the rollers80, 8| which hold back the work to the feed desired,the dog slippingslightly over the work to compensate therefor;

In many cases it is desirable to locate the first skipped stitch apredetermined distance from the edge of the work at the beginning of thestitching operation and to indicate the number of stitches that havebeen made after 'a skipped stitch when the machine is stopped; and toaccomplish this result we have shown an indicator disc 81 mounted on thecountershaft 24 and having a series of graduations 88 corresponding innumber to the number of stitches to be made in the work per inch. Asshown, there are twelve graduations corresponding to twelve stitches perinch, and for convenience the zero graduations correspond to a skippedstitch. The disc 81 cooperates with a pointer 88 mounted in convenientrelation on the machine, and the parts are so related that when thefollower roller l8 engages the cam recess 28 for skipping a stitch thezero graduation on the indicator stitch is in juxtaposition to thepointer 88. Therefore should it be desired to form six stitches inwardlyfrom the edge of the work at the beginning of the stitching operationbefore skipping a stitch the drive shaft D will be rotated until thegraduation 6" on the disc 81 is juxtaposed to the pointer 89. Then uponoperation of the machine six stitches will be formed followed by askipped stitch, and then continued operation of the machine will resultin the formation of eleven continuous stitches followed by a skippedstitch, and so on. To assist the operator in beginning operation uponthe next piece of work without unnecessary stopping of the machine, wemount on the disc a visible indicator Hill which may be a set screwadjustable circumferentially of the disc, and this visible indicatorwill be set in juxtaposition to the graduation on the disc which is injuxtaposition to the pointer at the beginning of the stitchingoperation, in the foregoing example, the graduation 8. Then when the endof one piece of work has passed the needle the operator will watch untilthe visible indicator i110 reaches the pointer 88 whereupon the machinewill be stopped. Then the next piece of work may be inserted into themachine and operation resumed with the assurance that the first skippedstitch on the second piece of work will be spaced the same distance fromthe edge as was the skipped stitch in the first piece of work. Thisfeature is particularly important where a long piece of facing strip toreceive fasteners is to be stitched to a plurality of gar ments insuccession.

In such cases the facing strip is fed through the feed rollers 80, 8|,but the garments are laid on top of the strip and do not pass throughthe feed rollers; and in some cases it is desirable to slightly modifythe feed of the tape and the garments especially where it is necessarythat the last slipped stitch shall be spaced approximately a certaindistance from the end of the garment at the completion of the stitchingoperation. In normal operation this distance may vary for differentreasons, particularly because of slight The sewing machine has the usualmechanism slip stitches is not changed. Howeven'the last generallydesignated A-A in Figure 2 such as shown in United States Patent No.718,988 dated .feed, the last slipped stitch will be too far from thegarment end, the feed mechanism will be adjusted to increase the lengthof stroke of the feed dog. Except for our feed rollers this wouldordinarily increase the length of stitches by increasing the length ofthe steps of feeding of the work, but in the present case the tape isheld back by the feed rollers and the material is substantiallynon-stretchable so that the length of the stitches is not increased.However, the feed dog does exert greater tension on the tape than duringnormal .feeding and takes up any slight slack there may be between thefeed dog and the rollers, and the garment follows the tape between thefeed dog and the presser foot a distance greater than the length of anormal stitch. The pressure of the presser foot on the work is less thanthe pressure exerted on the work by the feed rollers 80 and 8|, and thetape is held by the feed rollers while the garment is not so held, sothat the tape is under tension and the garment is not under tension.Therefore, at the end of the feeding movement when the feed dog retractsfrom and releases the tape and before the needle penetrates the garmentand tape, the ape slightly retracts sliding beneath the garment. and thegarment remains at the point to which it was fed. This results in therebeing slightly more of the garment than of the tape traversed by thestitch; in other words, the garment is slightly taken up or puckered andaccordingly the length of stitches remaining the same, the last slipstitch will be located closer to the end of the garment. Should theoperator discover that the last slip stitch with normal feed will be tooclose to the end of thegarment, the garment may be held backmanuallyagainst the influence of the feed dog. Ordinarily this wouldresult in changing the length of the stitches and distance between theslip stitches,

but with our machine, due to normal tendency of the feed dog tooverfeed, the backward tension or pull on the garment is compensated forby the overfeed, and as the tape is not retarded the length of stitchesor spac ng between the sl p stitch will be located farther from thegarment end.

Obviously, these adjustments of the feed may be used .in connection withother machines for skipping or slipping stitches in different ways,

and are not limited to our particular form of thread manipulatingmechanism.

While we have so far described the invention in connection with a singleneedlemachine. it may be used with a multiple needle machine. Forexample. another needle may be placed in the place provided in theneedle bar A alongside the needle 3, and threaded as s the needle 3.Then the gripper may be modified as shown in Fi ure .35 by forming thethread guide plate 90 with a hole 92 to receive both threads, or twoholes close together each to receive one thread so that both threads maybe located between the gripping surfaces 9| and 95. If' desired theclaim is:

nally of the jaw in either direction to move the threads from betweenthe gripping surfaces 94, 95 when it is not desired to slip stitches.With this construction two parallel lines of stitches It'll may beformed as indicated in Figure 36 and both threads may be caused .to slipstitches I02 at the same time and in juxtaposition.

This is important in securingfasteners with long shanks in thegapslbetween the plies of material beneath the slip stitches with theinner row of stitches adjacent the base of the fastener, to prevent thematerial being slid backwardly along the shanks so as to expose thelatter.

A similar effect can be obtained with a socalled zig-zag stitchingmachine having an oscillatory needle which may be periodicallyoscillated to form transverse stitches I03 at opposite sides of aslipped stitch I04 as shown in Figure 3'7. The transverse stitches I 03serve the same function as the two lines of stitches of IM in preventingthe fabric strips from sliding along the shanks of fasteners that aredisposed beneath the slipped stitches.

It will be observed that in all forms of the invention thecharacteristic features are the sk pping stitches by pulling of thethread instead of by modifying or manipulating the stitch formingmechanism or the bobbin mechanism, and the means for controlling theskipping of the stitches is substantially independent of the stitchforming mechanism and work feeding mechanism. Moreover, the mechanism issimple and reliable in.

roller 32 since undue wear of these parts would materially affect theaccuracy of the o erat on of the gripper jaws, it being understood thata very delicate relationship must obtain between the movement of thegripping jaws and the thread and needle to ensure pulling out of thethread loop and at the same time obviate breaking of the thread.

Furthermore, due to the independent relation of our thread manipulatingmechanism to the stitchforming and work feed 'mechanism of the sewingmachine, the machine may be operated at substantially its usual highspeed; our invention does not hinder, impede or slow the speed ofstitching as would be the case were the operation of the needle bar orbobbin mechanism modified to slip stitches.

Having thus described our invention, what we 1. In a machine of thecharacter described the combination with work feed mechanism and stitchforming mechanism including a reciprocating needle and a loop takeroperable n tim d relation for forcing a thread through a p ece of workforming a loop in the thread at one side of the work and interlockinganother thread through said loop to normally form a line of needle toexert tension on the thread as the needle rises from work penetratingposition to prevent formation of loops.

2. The machine set forth in claim 1 wherein the means for operating thegripping means to grip the thread and said means for actuating thegripping means in timed relation to movement of the needle, actuate thethread gripping means as the needle rises from the work to maintain thethread substantially taut between said gripping means and the point ofinterlocking of the threads in the last previously formed stitch.

3.1n a machine of the character described the combination with work feedmechanism and stitch forming mechanism including a reciprocating needleand a loop taker operable in timed relation for forcing a thread througha piece of work, forming a loop in said thread at one side of the workand interlocking another thread through said loop, of a gripper forgripping the needle thread above the needle, means operable at slowerspeed but in timed relation with said needle for automatically actuatingsaid gripper at intervals to grip said thread while the needle is abovethe work and maintain said grip during movement of the needle into andout of the work, and means operable approximately synchronoifsly withsaid needle during a portion of each of the descending and ascendingmovements of the needle but at slightly greater speed during the firstportion of the movement of the needle from the limit of its workpenetrating position to actuate said gripper to exert tension, on theneedle thread and prevent formation of a loop.

4. The machine set forth in claim 3 wherein the means for automaticallyactuating the gripper at intervals actuates said gripper to grip saidthread when the needle is at approximately its uppermost position andalso actuates said gripper to release said thread while the needle is atapproximately its uppermost position.

5. In a machine of the character described the combination with workfeed mechanism and stitch forming mechanism including a reciprocatingneedle and a loop taker operable in timed relation for forcing a threadthrough a piece of work, forming a loop in said thread at one side ofthe work and interlocking another thread through said loop, and a driveshaft and operative connections between it and said stitch formingmechanism, of a gripper to grip the needle thread above the needle, acam shaft geared for reduced speed to said drive shaft, a cam on saidcam shaft and operatively connected to said gripper for actuating saidgripper at intervals to grip said thread while the needle is atapproximately its uppermost position, and to release said thread whilethe needleis in said position, and a cam on said drive shaft operativelyconnected to said gripper for moving the gripper approximatelysynchronously with said needle during a portion of the descending andascending movements of the needle but at a greater speed than the needleduring the first portion of its movement from the limit of its workpenetrating position to exert tension on the needle thread and preventformation of loops.

6. In a machine of the character described the combination with workfeed mechanism and stitch forming mechanism including a reciprocatingneedle and a loop taker operable in timed relation for forcing a threadthrough a piece of work, forming a loop in said thread at one side ofthe work and interlocking another thread through said loop, o'fa gripperincluding two opposed jaws normally yieldingly influenced toward eachother to grip, the needle thread above the needle, means for moving saidgr pp r approximately synchronously with said needle during a portion ofeach of the descending and ascending movements of the needle but atslightly greater speed during the first portion of the movement pf theneedle from the limit of its work penetrating position, means forstarting and stopping said movement of said gripper while the needle isat approximately its uppermost position, and stationa means to beengaged by and separate said jaws to release the thread when the needleis at approximately its uppermost position and to release said jaws andto grip said thread as the needle begins its descent from said uppermostposition, whereby said gripper will pull said thread as the needle risesfrom its work penetrating position to prevent formation of a loop.

'7. The machine set forth in claim 1 wherein said gripping meansincludes two relatively movable opposed jaws and spring means fornormally yieldingly drawing them together to, grip the thread, and saidmeans for actuating the gripping means to grip the thread relativelymoves saidjaws to separate them and permits the spring means to movethem toward each other.

8. The machine set forth in claim 1 wherein said gripping means includestwo relatively movable opposed jaws and spring means for normallyyieldingly drawing them together to grip the thread, and a horizontalshaft connected at one end to both said jaws to oscillate the jaws in avertical plane with the needle thread between them, said means foractuating the gripping means to grip the thread relatively moves saidjaws to separate them and permits the spring means to move them towardeach other, and the means for actuating the gripping means in timedrelation to movement of the needle thread by the needle oscillates saidshaft.

9. The machine set forth in claiml wherein said gripping means includestwo relatively movable opposed jaws, said means for actuating thegripping means to grip the thread includes a cam operatively connectedto one of the jaws to control movement of the latter toward and from theother jaw, and a horizontal shaft connected at one end to both said jawsto oscillate the jaws in a vertical plane with the needle thread betweenthem, and said means for actuating the gripping means to exert tensionon the thread includes a cam rotatable in timed relation to the movementof the needle, and an operative connection between said cam and saidshaft to oscillate said gripping means.

10. The machine set forth in claim 1 with the addition of a common meansindependent of the stitch forming mechanism for controlling starting andstopping of the means for actuating the gripping means to grip thethread and the means for actuating the gripping means to exert tensionon the thread.

11. The machine set forth in claim 5 with the addition of means forconnecting and disconnecting said gripper from said two camsindependently of the operation of said stitch forming mechanism.

12. The machine set forth in claim 8 with the addition of means forcontrolling starting and stopping of the means for moving the gripperwith the needle independently of. the stitch forming mechanism.

13. Th' machine set forth in claim 1 with the position.

14. The machine set forth in claim 3 with the I addition of means forcontrolling starting and stopping of the means for actuating thegripping means to grip the thread and the means for actuating thegripping means to exert tension on the thread independently of theoperation of said stitch forming mechanism and only while the needle isat approximately its uppermost addition of means for controllingstarting and stopping of the means for actuating the gripper to grip thethread and the means for actuating saidgripper to exert tension on thethread independently of the operation of said stitch formtng mechanismand only while the needle is at approximately its uppermost position.

I 15. The machine set forth in claim 5 with the addition of a controlslide to separably engage the operative connection between said cam onthey drive shaft and said gripper when the needle 8 at approximately itsuppermost position to disconnect and hold disconnected said operativecon-- nection from said cam to stop movement of said gripperindependently of said stitch forming mechanism.

16; The machine setforth in claim 5 with the addition of a control slideto separably engage the operative connection between said cam on thedrive shaft and said gripper when the needle is at approximately itsuppermost position to disconnect and hold disconnected said operativeconnection from said cam to stop movement of said. gripper independentlyof said stitch forming mechanism, and means for disconnecting andholding disconnected from said cam on the cam shaft the operativeconnection between said cam and said gripper substantiallysimultaneously with disconnection of said cam on the drive shaft fromsaid gripper.

17. The machine set forth in claim .5 with the addition of meansincluding a stationary pointer and an indicator disk on said cam shaftto cooperate with said pointer for presetting the machine to form apredetermined number of stitches prior to operating said threadmanipulating means to prevent formation of a loop and slip a stitch.

18. In a machine of the character describedthe combination with workfeed mechanism and stitch forming mechanism including a reciprocatingneedle and a loop taker operable in timed re-- lation for forcing athread through a piece of work, forming a loop in said thread at oneside of the work and interlocking another thread through said loop, anda drive shaft and operative connections between it and said stitchforming mechanism, of a gripper to grip the needle thread above theneedle including a pair of opposed relatively movable jaws and ahorizontal shaft connected to one end of each jaw for oscillating thejaws in a vertical plane with the needle thread between them, a camshaft geared for reduced speed to said drive shaft, a cam on said camshaft and an operative connection between said cam and one of saidgripper jaws to control movement of said jaws toward and from the otherat inter-- vals to grip and release the needle thread when the needle isapproximately in its uppermost position, a cam on said drive shaft, andan operative connection between said cam and said gripper shaft tocontrol oscillation of thelatter to swing said gripper approximatelysynchronously with said needle during a portion of each of thedescending and ascending movements of the needle but at a greater speedthan the needle during the first portion of its movement from the limitof its work penetrating position to exert tension on the needle threadand prevent formation of loops.

19. The machine set forth in claim 5 with the addition of means forpreventing said operative connection between said cam on the driveshaftand said gripper from engagement with said cam except at intervalscorresponding. to the intervals at which the gripper grips said thread.

20. In a machine of the character described the combination with workfeed mechanism and stitch forming mechanism including a reciprocatingneedle and a loop taker operable in timed relation for forcing a threadthrough a piece of work, forming a loop in said thread at one side ofthe work and interlocking another thread through said loop and a driveshaft and operative connections between it and said stitch formingmechanism, of a gripper to grip the needle thread above the needleincluding a pair of opposed relatively movable jaws and a horizontalshaft connected to one end of each jaw for oscillating the .jaws in avertical plane with the needle thread between them, means operable intimed relation to the needle for controlling actuation of said movablejaw toward and from the other jaw at intervals to grip and release saidneedle thread above the needle when the needle is in approximately itsuppermost position, a cam on said drive shaft, a follower lever pivotedat one end one, fixed support and connected at its other end to saidgripper shaft so as to rotate said gripper shaft in one direction uponmovement of said follower lever by said cam to swing said gripper, and aspring for rotating said gripper shaft in the other direction.

21. The machine set forth in claim 1 wherein the means for actuating thegripping means to grip the thread is constructed'to actuate the grippingmeans into gripping relation to the thread only while the needle is atapproximately its uppermost position and also is constructed to actuatethe gripping means to release the thread when the needle is in saidposition.

22. The machine set forth in claim 1 with the addition of a positiveauxiliary work advancing device ahead of said work feed mechanismoperable in timed relation to said stitch forming mechanism to supplythe work to the work feed mechanism at a predetermined rate and whereinsaid work feed mechanism is adjusted to slightly overfeed but moverelatively to the work without feeding after the amount supplied by theauxiliary device has been fed, so as to ensure accurate spacing of theskipped stitches.

23. The machine set forth in claim 3 with the addition of a positiveauxiliary work advancing deviceahead of said work feed mechanismoperable in timed relation to said stitch forming mechanism to supplythe work to the work feed mechanism at a predetermined rate, and whereinsaid work feed mechanism is adjusted to slightly overfeed but moverelatively to the work without feeding after the amount supplied by theauxiliary device has been fed. so as to ensure accurate spacing of theskipped stitches.

25. The machine set forth in claim 6 with the addition of a positiveauxiliary work advancing device ahead of said work feed mechanismoperable in timed relation to said stitch forming mechanism to supplythe work to the feed dog at a predetermined rate, and wherein said workfeed mechanism is adjusted to slightly overfeed but move relatively tothe work without feedin after the amount supplied by the auxiliarydevice has been fed, so as to ensure accurate spacing of the skippedstitches.

26. In a machine of the character described the combination with workfeed mechanism and stitch forming mechanism including a reciproeatingneedle and a loop taker operable in timed relation for forcing a threadthrough a piece of work, forming a loop in the thread at one side of thework and interlocking another thread through said loop to normally-forma line of stitches, of means for gripping said thread at intervals, andmeans operating in timed relation to the gripping of said thread and themovement of the needle and said loop taker for moving said grippingmeans while the thread is gripped and in the same direction as themovement of said needle and exerting tension on the thread as the needlerises from work penetrating position and prior to the reaching ofloop-taking relation between the loop taker and the needle thread toprevent interlocking of said threads.

27. The machine set forth in claim 26 wherein said gripping means andthe means for moving said gripping means and exerting tension on thethread, are operated to maintain the grip on the thread as the needlerises and keep the thread substantially taut between the point ofgripping and the needle to prevent entanglement of the surplus threadwith the needle.

28. Thecombination with a sewing machine comprising work feedingmechanism, stitch forming mechanism including a needle and needle threadfor forming a line of stitches, and means for causing slipping ofstitches at intervals, of

means to grip the needle thread, and means for controlling. actuation ofsaid gripping means automatically into gripping relation to said needlethread at intervals, and means to move said gripping means while thethread is so gripped to carry to a point above the needle the surplusthread'which is present as the result of the slipped stitches.

29. The combination with a sewing machine comprising work feedingmechanism, stitch forming mechanism. including a needle and needlethread for forming a line of stitches, and means for causing slipping ofstitches at intervals, of means to grip the needle thread, and means forcontrolling actuation of said gripping means auto- 'matically intogripping relation to saidneedle thread at-intervals and to move to apoint above the needle the surplus thread which is present as the resultof the slipped stitches, said gripping means including -two relativelymovable opposed Jaws to grip theneedle thread between them and pivotallymounted at one end to move together in approximately the plane of move-'ment of the needle.

30. In a machine of the character described the combination with workfeed mechanism and stitch'forming mechanism including a reciprocatingneedle and a loop taker operable in timed relation for forcing a threadthrough a piece of work, forming a loop in the thread at one side of thework and interlocking another thread through said loop to normally forma line of stitches, of means operable in timed relation to the movementof the needle thread by said needle to automatically manipulate saidthread at intervals during normal operation of the stitch formingmechanism and work feedmechanism in forming a stitch to preventinterlocking of said threads; 8, positive auxiliary work advancingdevice ahead of said' work feed mechanism operable in timed relation tosaid stitch forming mechanism to supply the work to the work feedmechanism at a predetermined rate, and said work feed mechanism beingadjusted to slightly overfeed but move relatively to the work withoutfeeding after the amount supplied by the auxiliary device has been fed,so as to ensure accurate spacing of the skipped stitches.

HERMAN ROSENMAN. LEO ROSEMAN.

